This invention relates to a separator for successively grasping or seizing threads from an array. The separator includes a frame in which needles are slidably guided and driven in opposite directions. Each needle has a hook(s) freely disposed in a gap in the frame for seizing the foremost thread in the array.
Such separators are employed in weaving machines for joining the two ends of a fabric by a woven seam. The endless fabrics formed by such a seam are used, for example, as sheet formers in the wet section of a papermaking machine. At each end of the fabric, the ends of the warp threads are held by a woven strip in the sequence determined by the weave. Separators are employed to take the warp threads from the woven strip in accordance with this sequence, i.e. to separate them. The separated warp threads are then introduced into the shed of the seam weaving machine. It is essential that the sequence of the warp threads is strictly maintained since otherwise flaws occur in the woven seam which mark the paper. Such a seam weaving machine is disclosed in U.S. Pat. No. 4,410,015.
A separator of the type described is disclosed in DE-U-81 22 450, wherein the thread to be seized is urged by the hook of a single needle against the frame and thus firmly clamped. Since the thread is interwoven in the array, i.e. in the woven strip, and for such clamping the thread must be shifted upwardly or downwardly, the thread occasionally becomes detached from the hook. With the known separator, there is also a risk that two threads become seized by the hook. Although this is signalled by a keystroke on the needle, the seam weaving machine comes to a standstill. Especially when double-layer or multi-layer sheet formers are made endless, there is a high risk that two threads may be seized simultaneously by the separator.